Indicator for cartridge type fuses



July 2 1940- w. c. LlN'roN 2,206,784

INDICATOR FOR CARTRIDGE TYPE F'USES Filed March 6, 1939 agg. 1.

"j my? Patented July 2, 1940wir UNITED STATES PATENT OFFICE INDICATOR FOR CARTRIDGE TYPE FUSES Application March 6,1939, serial No. 260,159

4 Claims.

The present invention relates to indicators for ferrule, knife blade and other conventional types of cartridge fuses and preferably an indicator therefor which will give off a visible signal or inli dication when the thermal element of the fuse becomes blown or ruptured, whereby one"mav readily ascertain the particular fuse that needs ,replacement to again establish a completed electrical circuit. Such indicators employ a minia- 30 ture neon glow lamp having a leak resistance connected in series with the contact terminals oi the fuse in order that when the fusible element is blown or ruptured, which latter is also connected to the contact terminals of the fuse but 15 in parallel to the glow lamp. the current will pass to the lamp for causing the lat-ter to become lluminous and thereby function as a Visible indicator. The invention more particularly relates to the mechanical construction of a casing having such lamp indicator as well as means for effecting an electrical and mechanical connection between the indicator and all types of cartridge fuses.

Amongst the principal objects of the invention f3 is to provide a casing for fuse indicators which can be molded from suitable molding powders or materials with a metallic insert permanently attached tb the finished casing and which inw will provide means for mechanically attaching 5"" the lamp to the casing as well as establishing an electrical Contact terminal for the lamp.

Another equally important object of the invention is to provide a sectional casing for lamp indicators whereby each section may be prepared from molding materials with metallic insert, therein and when said sections are connected together. the glow lamp will be properly housed therein and the metallic inserts serve as contact terminals, all of which not only materially redo duces the cost of manufacture and assembly of the parts of the indicator, but provides new and novel means for facilitating a mechanical and Velectrical connection between the indicator and the terminals of conventional types of cartridffe 45 fuses.

A still further object of the invention is to provide means whereby lamp indicators may be easily and readily attached to any cartridge type of fus? without dismantling or materially alter- 50 ing the latter and when attached, will permanently and rigidly connect the indicator to cartridge fuses whereby it may also serve as a handhold for the fuse for facilitating the insertion in or removal from the fuse clips of a standard 55 cutout base.

(Cl. 20D-121) And still another object of the present invention is to provide an indicator of new and novel construction in that the several parts thereof may be economically constructed and assembled, thereby materially reducing the cost associated 6 with the manufacture thereof and rendering the same commercially desirable.

Other objects of the invention will be in part obvious and in part pointed out hereinafter.

In orller that the invention and its mode of ll) operation may be readily understood by persons skilled in the art, I have in the accompanying drawing and in the detailed following description based thereupon, set out an embodiment of the same.

In the drawing:

Fig. l is a vertical longitudinal section taken through my indicator as applied to a cartridge fuse and the latter being illustrated in dotted lines.

Fig. 2 is a vertical transverse section taken on the line 2-2 of Fig. 1 in the direction of the arrow points.

Fig. 3 is an end elevation of the indicator having spring Contact clips or fingers for detachably connecting the indicator to the conventional type of knife blade fuses.

Fig. 4 is a top plan view of the indicator.

Fig. 5 is a longitudinal section through one section of the casing.

Fig. 6 is a vertical longitudinal section through the other section of the casing.

Fig. 7 is a top plan View of an indicator as applied to a cartridge type fuse illustrating a slightly modified form of the invention.

Fig. 8 is a vertical longitudinal section of the indicator' as is illustrated in Fig. 7, and

Fig. 9 is an enlarged vertical transverse section taken on the line 9-9 of Fig. 8 in the direction of the arrow. 40

Referring now more particularly to the accompanying drawing wherein like and corresprmdinT parts are designated by similar reference chai actors throughout the several views. I have here in illustrated a cartridge type fuse consisting of a cylindrical body portion I having mounted upon the opposite ends thereof the usual metallic terminal caps or ferrules 2, which latter are dcsigned for detachable connection with the usual terminal clips arranged within a fuse box. whcreu by the cartridge fuse may be inserted in the desired electrical circuit. Arranged within the casing l is the usual fuse link or terminal element for protecting the electrical circuit to which the fuse is included, whereby, should an eXcesdiameter throughout. andfone en thi molding of. ,thief/@Sme e, metall secured. within 0116; 6nd-- hfFOfff.

I section "I of the casing illustrated :in Figwl l20,15 .th

i sivey current ilow through the fuse link of the fuse, it will become blown or ruptured. In order to designate the inoperative or blown condition of the fuse link, indicating means such as a glow lamp 3 may be employed and this glow lamp has one lead wire 4 thereof connected to one of the terminal caps 2, whereas, the other lead wire in series with the terminals 2 and the glow lamp is also connected in series with these terminals 2 but in parallel to thef-ffuse linkiiwherebyiwher! the latter becomes blown or ru tured,n the u will pass through the glo ter to give oi a visiblesignal'or'nd the fuse link has become blown an replaced. :ist i' The present invention resides in, y y i novel construction of a housing for the' 'g'lw' lamp 3, .which latter, may befdetachahlyfor; permanent- `t suitable insulafing materials suchiasyBke. "a

t ,Thetseeaoniofthetubularzcasine Sprefrbly u moideetfrom-en: opaqueiinsulating matertel/pro- H viding achamber, tthereiniwh'ih 's fit-the .Same

is ,prov-medwith a; reduced extension from the inner wall of the casing adjacentgthe end thereof upon which the redgicedgeitension 1s ceiving a leak resistance I2 which is connected to the `lead Wire. 5 of lthe glowAt larnp,: ,-Thef'other t section .6 .of 'fthe-'casing isffnrefrably molded from a transparent or translucent materiahhaving; a

formed therein an` `openin recess I'I.

In assemblingvth This :lead `wire 4 is connected :tothe .metallicemsert,` I-Il.-byf;plac ing solder I8 within the enlarged-recess;I'I;in the manner aslis alsoillustrated,inEigh1ftot the drawing. Therother ileadfawire;tf5mofltlieplanllp projects in anopposite'directioneto that ofthe lead wire 4 andhastonerextremitmseatedfwithin the channelway` '.formedby the.- parallelgfwalls or projections I I'..-q; A` Wire `19 Lhaslonegextrem-ity ralso projecting, wi thin the 'channelwayformed,` fby. vthe projectionsy I I andln thisfchan'nelwayfis inserted a'plastic resistor. compositiongwhich not only; retains the terminalsfofY the:iwires-,rtandIStbetween the `walls -II ybut acts;asafleakwresistance for preventing excessive :current 5 fromffliowing through the lelectricalcircuit and; at ithensanie time, .permitsl sufficient leakage; of, currentjto the lampl: which. would vcause-the-;latter-;to: glow.

Utente a.

)molde- ASlt ia., :lead V,wire IZtl...

The opposite extremity of the wire i9 is then insertedthrough the openingr I S of the metallic insert I3 molded with the section S of the casing. After the wire I9 is placed in position, the reduced extension 9 of the section 'I is inserted within the enlarged recess I4 formed within the section 6 and cement applied thereto for permanentrlyy fastening these VseC rt,iOiI r1L tgether. The

`which yprojects through tallic insert is connected rv to this insert by inserting solder 2@ Within the recess Il formed within this insert, whereby, the aqrrnrwilll .bewcornpletely housed within the tubular casing and nnectueld together with the leak re- `nice(I2-1n-1Sries with the extensions l5 of the nie inserts.

o'r'n'th'abovearrangement, it is obvious that @thea-lamp isntirely housed Within the opaque sectionovf the casing and when the lamp glows, the -raysibf light will be indirectly projected through he `transparent sectionfgofthe casing. By so `-ging lainpwithin thecasing, the transseycgtiorrf maybernolded from transparent st materialsof various colors so thatthe rays eht "fre sing the particularscolor of the` transparent ,.fllliie,v ,partioulamcolors employed may .th

, .t l .,fo; 9:1D431U-.SVQ-:Of'thetdfaw- I Il v,the housingzforrtheyvlamp consists of a tubular y,caisingjf 2| Jwhd h `is.y preferably; molded from a an parent `-r rtranslucent `material f such as Iin one end of this-,tubular casing I l` l,uherewitha metallic insertr22- The lead wire 4 of the glow lamp 3 extends through i an peningvriorrnedewithinfthismetallic insert c an f 1ST: @este edle/,thereto @remets Off the Solder -I A wlgiereas-,the `opposite leadrwire 5 of the lamp connectedto a leahresistorfZ and the oppoeend of' this. leak-resistor yhas connected thereto n 1A.metallicplugZllisI then inywithin theopenled eindI of the casingZ tand adwir 26,.1projeclts through an opening lugrl2vl and yis connected to Y' ,thesolder 2 8..V yThe-metallic 2 :h `s a ,threaded recess formedtherein ,The Oppositeinetallic cap 2 of the fuse has ment,it is quite obvious that by turning thccasing ,-12 i. -upon the;screw 29,,it,jwillbepivotally con` ,.nected 1toonetxpfthe,termi nal caps 2 of thefusc ,andqduring-gthe, turning movement ,ofi the casing v2l,;tthe`plugf24 willgpass by theT-shapcd ond of --thebolt'30 duentothertransversc slolI formed thereinbutpafter ;tlie,casing 2l has been propverly-,seated uponttheterrninal caps 2. solder 3l Umaygbe placedfiipon the oppositcfsides of thc .*boltlwithingthe Tfsliaped slot of theplug 2l,

whereby, a further turning movement of the fuse the g lamp wivlvlf 7project from t the i, ch isl seated a'A headless :screw29 rvand the gerente @nd Qfthi St-SC,rtwy ZSviVSfseeted Within a :-,.t,h;readed v,re/cesser ,opening tforrncd :within one of themetallic capsw-orjferrules `of the cartridge .l-frusye.

y,yalso,atthreagied recess orgopening formed therein v,which?recciveshrthc; threaded end ofma T-shaped g-.,boltg3(l,. Thernetallic plug 2l' has Lformed thorein a,H1-shapedslot-throughwhich .projects the ....uppler'pnd ,of the boltglly-From this arrangecasing 2| will be prevented and the casing permanently afllxed to the metallic ferrules 2 of the fuse.

Instead of permanently attaching the indicator to the fuses, any suitable means may be employed for detachably connecting the indicator to the contact terminals of lthe fuse such as the spring clips 32, each of which may have one end welded or otherwise secured to the lug projections- Il formed with the metallic inserts I0 and I3. These spring contact fingers or clips 32 are sprung over the ends of the terminal caps 2 of the cartridge fuse and by this arrangement, it is obvious that the indicator will be detachably connected to the fuse but the casing of the indicator provides a handhold for inserting or ejecting the fuse from the clips of a cutout base included in the electrical circuit to which the fuse is applied.

When applying my indicator to the usual and conventional form of knife blade cartridge fuses 33, I provide a spring clip 34 of the construction as illustrated in Fig 3 of the drawing, which clips 34 are welded or otherwise secured to the lug projections I5 of the metallic inserts I 0 and I3. These spring clips 34 are capable of being inserted over the bladed terminals 35 of the fuse 33 in order that these blades 35 may be seated within the slots 3B, whereby, the fuse casing will be detachably connected to the cartridge fuse but yet retained in proper position thereupon.

Other forms of mechanical connection between the indicator and the cartridge fuse may be employed but in any event, a proper electrical connection must be effected between the lug terminals l5 of the indicator and the contact terminals 2 of the fuse, whereby, the lamp and leal:v resistor will be connected in series with the terminals of the fuse but in parallel to the thermal element or fuse link connected to these contact terminals of the fuse, whereby, when the fuse link becomes blown or ruptured, the lamp 3 will be rendered operative for giving off a visible signal, indicating the inoperative condition of the fuse link or thermal element of the fuse.

Manifestly, the construction herein shown is capable of considerable modification and such modifications as come within the scope of my claims, I consider within the spirit of my invention.

I claim:

l. An indicator for electrical fuses comprising a sectional casing formed from molding materials and each section having a compartment formed therein, a metallic insert embedded in and molded with one end of each section of'the casing, the Walls of one section of said casing being opaque, a glow lamp arranged within the compartment of the section having opaque walls, a pair of parallel walls formed with the inner face of one section of the casing and projecting within the compartmentformed therein, a leak resistor arranged between said walls, means for connecting the sections of the casing together, means for connecting said lamp and leak resistor in series with said metallic inserts and conductors connected to said metallic inserts.

2. An indicator for cartridge type fuses having a pair of spaced contact terminals, a threaded bolt connected to one of the terminals of said fuse, a T-shaped bolt connected to the other terminal of said fuse, a casing, metallic inserts secured to said casing, a glow lamp arranged within said casing having its lead wires electrically connected to said metallic inserts, one of said metallic inserts having a threaded recess formed therein for receiving the threaded bolt attached to one contact terminal of the fuse, the other metallic insert having a substantially T-shaped slot formed therein for receiving the T-shaped bolt connected to the opposite contact terminal of the fuse and solder arranged within said T-shaped slot of the metallic insert about said T-shaped bolt substantially as and for the purpose specified.

3. An indicator for electrical fuses comprising a pair of translucent sections, means for connecting said sections together forming a casing, a pair of metallic inserts each formed within one end of one of said sections, a glow lamp with leak resistor arranged within said casing and connected in series with said metallic inserts, and means for connecting said inserts to a fuse.

4. An indicator for electrical fuses comprising a pair of translucent tubular sections, means for connecting an end portion of said sections together, a pair of metallic inserts each directly connected to and closing the free end of one of said sections, an extension formed 'with each. l

lamp with leak resistor positioned Within said connected section and connected in series with said inserts.

WILLIAM C. LINTON. 

